JPH0687361B2 - Fluorescent lamp lighting device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluorescent lamp lighting device, and more particularly to a fluorescent lamp lighting device suitable as a light source for a liquid crystal display device used in a vehicle or the like.

[Background of the Invention]

The use of a fluorescent lamp as a light source of various display devices is generally widely known and adopted.

However, if the fluorescent tube itself is divided into a light emitting surface and a discharge portion, the light quantity (luminance) of the discharge portion is inferior to that of the light emitting surface, and when preparing it as an instrument panel for a vehicle, uneven lighting occurs and it is averaged. It was necessary to devise the mounting surface or the arrangement of the fluorescent tube. It is also practically used for lighting signboards, etc. by providing a light-shielding curtain between the light emitting surface of the fluorescent tube and the illuminating surface to make the illuminating surface uniform, but to make it thinner and smaller as a lighting device. Has a limit and is not suitable for instrument panels.

Further, as disclosed in Japanese Patent Laid-Open No. 58-198850, there is also known one in which a cylindrical mesh heater is provided around the fluorescent tube so as to cover the light emitting surface, but the mesh heater is simply arranged in a grid pattern. Since it is a steel body and there is a gap between it and the fluorescent tube, it is possible that the light diffuses and is blocked and the overall brightness is reduced.

[Object of the Invention]

An object of the present invention is to easily provide a fluorescent lamp lighting device with a constant light amount (luminance).

[Outline of Invention]

When a fluorescent tube is used as the light source of the illuminating device, the brightness in the vicinity of the discharge part (filament part) is lower than that in the light emitting surface (central part), so that it cannot be effectively used as lighting. Therefore, by providing a light-shielding device that returns the amount of light on the light-emitting surface to the inside of the fluorescent tube appropriately, it is possible to suppress the brightness more than necessary, and at the same time, the amount of light returned to the inside of the fluorescent tube causes more light to be emitted from the vicinity of the discharge tube. Also in the case of (3), good brightness can be obtained.

Example of Invention

 Hereinafter, description will be given based on an embodiment shown in the drawings.

FIG. 1 is a partial cross-sectional view showing a mounted state of an instrument for a vehicle. The fluorescent tube 1 has a glass tube coated with a fluorescent substance as usual, and argon gas and mercury vapor are enclosed. Has been done. A filament 4 which is airtightly fixed to the metal fitting 2 and electrically connected to the lead power source 3 is provided at both ends of the fluorescent tube 1, and a discharge part 5 is provided around the filament 4.
Are formed.

On the other hand, a light-shielding means such as a light-shielding curtain 6A for increasing the amount of light around the discharge portion and suppressing the amount of light on the light-emitting surface is formed on the light-emitting surface 6 between the discharge portions.

Reference numeral 7 is a liquid crystal display element, 8 is a light diffusion / transmission plate, and 9 is a reflection plate.

2A and 2B, the light-shielding curtain 6A will be described in detail. For example, aluminum foil 6b having a high light reflection efficiency is scattered on the surface of a transparent polyester film 6a in a mesh shape by vapor deposition or the like. The light-shielding curtain 6A is at least formed, and in the first embodiment, aluminum foils of uniform size are arranged at equal intervals. The light-shielding curtain 6A thus formed is wound around the light emitting surface 6 of the fluorescent tube 1 and fixed by adhesion.

Now, when a voltage is applied through the lead electrode 3, the ultraviolet rays generated by the discharge from the filament 4 are converted into visible rays for illumination, and the conventional light amount shown in FIG. 3 (A)-[I] is used. Curve (high on the light emitting surface and low on the discharge part)
On the other hand, a part of the light amount is returned to the inside of the fluorescent tube 1 by the light-shielding curtain 6A provided on the light emitting surface 6, and the light is repeatedly reflected in this fluorescent tube to shift the amount of light higher than necessary to both ends. Radiation from the vicinity of the discharge section 5 (see FIG. 3 (A)-[II]) Generally, the rate of increase in brightness at both ends of the fluorescent tube is determined by the degree of shading of the light emitting surface, but as necessary. It can be arbitrarily determined. If the light-shielding curtain 6A is located on the outer peripheral portion away from the fluorescent tube 1, the reflection effect due to the light-shielding curtain cannot be expected, and the brightness increases at both ends of the fluorescent tube as shown in FIG. 3 (A)-[III]. However, the brightness is lowered as a whole.

According to the above-mentioned embodiment, by merely winding the light-shielding curtain having the reflecting function around the light emitting surface of the fluorescent tube 1, the brightness of the discharge part where the light intensity is low is increased and the part where the light intensity is high is suppressed, so that the unevenness of the whole is averaged. The amount of light that cannot be obtained can be obtained, and the region is expanded by 10 to 20 mm at both ends, and the light emitting surface of the fluorescent tube 1 can be widely and effectively used.

The second embodiment will be described with reference to FIGS. 4 (A) and 4 (B). The light-shielding curtain fixed to the light emitting surface 6 of the fluorescent tube 1 is an aluminum foil attached to the surface of the polyester film at the center. Texture gradually goes from both sides to the discharge section,
That is, the structure is such that the light transmittance is gradually increased and the reflectance is decreased. This structure can be easily obtained by arranging an aluminum foil having a large area on the surface of the central portion of the polyester film, and gradually arranging aluminum foils having small intervals on both sides thereof.

According to this configuration, the amount of light is shielded in the central portion of the fluorescent tube where the amount of light is relatively large, and the reflection is reduced toward both ends, so that the brightness as shown in FIG. 4 (A)-[II] From the center to the discharge part, it becomes almost flat, and the distribution of the light quantity is much better.

The above-mentioned two examples are described as an example in which the aluminum foil 6b is pasted on the upper surface of the polyester film 6a, but the same is true even if a punching hole is provided in the aluminum foil 6b by punching. The effect can be obtained, and the pores can have any size and shape depending on the required characteristics.

Further, the light-shielding curtain does not necessarily have to be attached separately, and even if it is formed at the same time when the fluorescent tube is formed, it does not hinder it. Further, the material is not limited to the embodiment as long as it has the same function.

The fluorescent lamp illuminating device obtained in this way can obtain a higher brightness than necessary for displaying, while suppressing the brightness of the central part of the fluorescent tube and simultaneously increasing the brightness of the tube surface of the low brightness part at both ends. You can It should be noted that the larger the amount of light shielding at the central portion, the higher the brightness at both end portions can be increased. As a result, the fluorescent tube itself can emit light more uniformly as a light source, and the area that can be effectively used as a light source expands by 10 to 20 mm at both ends, so the effective display area of the display device for the fluorescent tube length is large. On the contrary, there is an effect that the display device can be downsized to the display area.

〔The invention's effect〕

As described above, according to the present invention, it is possible to easily provide a fluorescent lamp lighting device with a constant light amount.

[Brief description of drawings]

The drawings show an embodiment of the fluorescent lamp illuminating device of the present invention. Fig. 1 is a sectional view of the mounting arrangement, Fig. 2 (A) is a development view of a light-shielding curtain, and Fig. 2 (B) is Fig. 2 ( II) II sectional view of A),
FIG. 3 (A) is a fluorescent tube long-luminance characteristic diagram corresponding to FIG. 3 (B), and FIG. 4 (A) is FIG. 3 (B) in another embodiment.
FIG. 3 is a diagram illustrating a fluorescent tube long luminance characteristic corresponding to FIG. 1 ... Fluorescent tube, 5 ... Discharge part, 6 ... Light emitting surface, 6a ... Film, 6b ... Aluminum foil.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-57-172603 (JP, A) Actually opened 59-22493 (JP, U) Actually opened 61-90106 (JP, U)

Claims (1)

[Claims] 1. A fluorescent lamp illuminating device comprising a fluorescent tube which is coated with a fluorescent substance and which is filled with argon gas or the like and which is illuminated by a discharge from an end of the fluorescent lamp illuminating device. A light transmitting portion and a light reflecting portion are formed in a scattered manner on the entire surface portion except the vicinity, and a part of the light emitted from this fluorescent tube is guided by the reflecting portion to the vicinity of the discharge portion in the fluorescent tube. , The density of the reflection part is made coarser as it goes from the central part to the discharge part so that the amount of light reflected by the light reflection part becomes smaller from the central part to the discharge part side, so that the brightness in the vicinity of the discharge part is increased. Adjust the amount of light so that it is equal to or higher than the brightness of other parts of the light tube, and wrap around the fluorescent tube a transparent polyester film with aluminum foil fixed to the light transmitting part and the light reflecting part. A fluorescent lamp lighting device characterized by being formed by attaching.